The building construction industry has employed interlocking, concrete building blocks for many years. Examples of such blocks can be seen in U.S. Pat. Nos. 1,434,612 to Hamilton; 1,499,493 to Simms; 2,351,768 to Kaping; 2,684,589 to Perreton; 2,887,869 to McKay; 3,376,682 to Briscoe; and 3,968,615 to Ivany.
The purposes of making building blocks interlocking include, inter alia, increasing the strengths of structures assembled with the blocks and decreasing the amount of skill required in building a structure with concrete blocks. By designing the block to increase the strength of the assembled structure, a builder or architect can achieve appreciable saving in the cost of materials. This results by reducing the requirement for expensive steel beam support members since the blocks themselves are capable of assuming increased amounts of the support function. By making the blocks interlock or interfit, the role which mortar plays in holding together horizontally and vertically adjacent blocks is also decreased and, thus, the need for skilled masons can oftentimes be eliminated. This enables less skilled workers to assemble a structure at a great savings in labor expense.
Although the prior art formed blocks represent strides in the art and have provided advantages over the commonly used rectangular shaped blocks the present invention provides advantages heretofore unknown in the art. A disadvantage of the known building block is the fact that the shapes thereof have caused the actual interfitting or interlocking portions to join in precisely and/or with difficulty. In most instances, the known interfitting construction blocks have increased the time required to assemble the blocks into a structure. Also, a number of the prior art blocks, when assembled, do not provide a flat interior and/or exterior walls. Still another disadvantage of the known blocks is that the interfitting portions of the blocks do not significantly add to the strength of a structure assembled therewith because the interfitting portions are too small and do not provide for even distribution of stress throughout all portions of the block. These and other shortcomings in the prior art blocks have demonstrated the need for an interfitting block which will overcome the existing problems.